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Converting sound level measurements in dbA to db

Converting sound level measurements in dbA to db

Converting sound level measurements in dbA to db

Does anyone know how to convert a sound level measurement made in dbA to db?
Where: db = 10log(Io/Ir)
dbA = sound measurement based on the 40 phon weighting curve

RE: Converting sound level measurements in dbA to db


You already have a measurement in dB.

The notation you have denotes a difference in dB from a reference level. The particular reference level is conveyed by the notation: dBA.

If you were to have an loss in your system, say a curtain that absorbed 30 dB of sound, you could subtract that directly from your source level in dBA to get a received level in dBA. This way, you can create a 'link budget', which accounts for all losses and gains in a system to determine your final signal level. This would still be referenced to the orignial level, in this case the 40 phon weighting curve.

The 40 phon weighting curve, is a tough one. The exact energy level varies according to the particular frequency measured. It becomes very complex when a variety of time-varying frequencies, such as are found in speech, are measured at the same time.

Also note that the proper notation is "dB". The "B" refered to is Alexander Graham Bell. Since it is a proper name, it should be capitalized. You may need to turn off the capitalization checker of your spell check (or put up with it), to write good memos.


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